Yu Liu’s early work mainly focused on the precipitation reconstructions in the arid-semiarid area of China using tree-ring data and he got some interesting results which showed the variations of the East Asian summer Monsoon front for the past 300-400 years. And these reconstructions also help us to understand the drought history in northern China. He used tree-ring data to forecast the precipitation variation trend in northern China and his forecast results had proven to be reliable so far.

He also works on tree-ring isotope.

His recent research interest shifted to the temperature reconstructions of the eastern Tibetan Plateau using tree-ring data. He and his colleagues found the temperature in the Tibetan Plateau varied synchronously with several temperature curves for Northern Hemisphere, which may be representative of the temperature history in northern China as a whole.